He was so angry that he wanted to tear the fellow with the caustic mouth apart with his bare hands. He wanted it so much, he had almost gone mad with the need to.
If not for the fact that there was nothing to gain from killing a sect member, he would have tried to kill this fellow now that they had lost their Dao Status and had become weaker.
If he killed his fellow devourer, all of the lifespan from the slain comrade would be taken by the sect. Then he would be fined by the sect on top of the loss. Part of his lifespan would be taken to compensate the sect for the loss of a disciple.
So, not only was there nothing to gain, but he had a lot to lose if he lost his temper and decided to rid himself and the world of this man. In order not to lose his temper, he decided to leave now while he still had enough willpower to restrain himself.
